THE TV coverage of our national week of mourning for Ronald Reagan is disproving the belief held by many that TV is good for nothing.

This week, TV has been good for something. No, not good – great. Also splendid, necessary and important.

Those who have chosen to skip the wall-to-wall coverage – because they think it’s overblown or they can’t shake their dislike for Reagan or they’re just not interested – are missing something special.

As Americans, we don’t get the chance to act like a country very often.

This week, though, the ceremonies marking Reagan’s death are giving us a rare opportunity to become reacquainted with national traditions that have not been on view for a generation.

The live coverage of the various events this week in California and Washington has been intensely moving and, at times, thrilling.

Among the most striking images so far: Honor guards bearing the president’s flag-draped coffin as military bands played “Hail to the Chief,” “America (My Country ‘Tis of Thee)” and “The Battle Hymn of the Republic”; and the incredible sight of 21 F-15 Eagle fighter jets flying in “missing-man formation” during Wednesday’s procession to the Capitol.

And then there are the mourners.

The sight of Nancy Reagan reaching out to smooth the flag on her husband’s casket will stay with us for a lifetime.

And when thousands of ordinary Americans filed somberly past the president’s body for hours on end in the Capitol rotunda (a continuous procession seen live yesterday on C-Span), it was a scene largely unchanged from the days of Lincoln.

In the evenings, the talk shows on the cable news channels have been extraordinarily thoughtful and informative.

Virtually every show has focused exclusively on President Reagan. Viewers intent on keeping up had to be especially dexterous with their remote controls.

Today, TV’s week of pomp and ceremony ends with a funeral service at Washington’s National Cathedral (scheduled to start at 11:30 a.m. and airing everywhere) followed hours later by a sunset burial in California.

The week has been one of those rare instances when TV fulfills its primary mission: To take us places we are unable to go ourselves and thereby allow us all to witness history in the making.